Simulation Analysis Of Static Pressure Gas Bearing Rotary Precision Based On CFD And Rotor Dynamic

Modern production technology with high precision has greatly promoted the development of test, optical electromechanical integration and precision machining technology. The precise air-bearing rotary stage, which is the major implementing agencie of potation measurement for the large-aperture aspheric surfacesm, has advantages of high precision, low friction and no pollution. Because the aerostatic gas bearing is a core component in the precise airbearing rotary stage, improving rotary accuracy of precise air-bearing rotary stage becomes the main content of aerostatic lubrication theoretical research and current pressurized gas bearing research.To study on the aerostatic gas bearing lubricating bearing of two-Axises airbearing rotary stage for recise rotary measurment, the governing equation of gas film flow field is set up based on aerostatic lubrication theory and computational fluid dynamics. A second-order upwind scheme is used to discretize the governing equation, the three-dimensional geometry model of bearing in gas film flow field is generated, the grid division of gas film flow fields is done with ICEM software, the simulation and analysis of the gas film flow field is performed with Fluent software; the bearing characteristic curves are obtained under different gas film flow fields and different film thickness. It can be shown that the structure of gas film flow field with with double-row pressure air supply holes and pressure groove has optimal bearing characteristics.Based on averaging effect of error and elastic simplified model of sliding bearing, the bearing characteristics of gas film flow field is simplified into elastic parameters of spring model. According to the different structures of gasn film flow field, equivalent model of the dynamics is obtained to solve the bearing rotation precision. When the main axle has roundness errors and dynamic unbalance, the influencing law of the different structures of gas film flow field on rotary precision of main axle has been analyzed. By comparing the obtained rotation precision variation curves of different structures of gas film flow field, the structure of gas film flow field with double-row pressure air supply holes and pressure groove has optimal rotation precision. It concludes that increasing the number of pressure equalizing grooves can improve stability of rotation precision. To verify the correctness of rotor dynamic model used to solve the bearing rotation precision, the rotary precision of main axle is obtained with numerical calculation method when the main axle has the same roundness error, and compared with the calculation result of dynamic equivalent model each other. It proves the feasibility of the established rotor dynamic model and the credibility of the result. The rotation accuracy of gas film flow fielding with different is analysed and calculated in this papper, which provides a new effective way to solve rotary accuracy of bearing.